In order to elucidate the enzymatic reaction mechanism for hydrophobic substrates, the hydrolysis rates for several substrates were measured in biphasic and microemulsion systems. We have also carried out preliminary experiments to investigate the characteristic behavior of membrane bioreactor. The following results were obtained.1. We measured the rate of hydrolysis of the homologs of 2-naphthyl ester by using a Lewis-cell to elucidate the mechanism of the lipase-catalyzed hydrolysis in biphasic systems. On the basis of the two-film model, it was found that the hydrolysis of these substrates proceeds at the interface. The interfacial reaction rate could be correlated by the Michaelis-Menten mechanism. The values of the rate constant and the Michaelis constant were almost independent of the kinds of 2-naphthyl ester and were much greater than those for the hydrolysis in the aqueos phase.2. The enzymatic reaction rates were measured in microemulsion, which is a suitable model system to
… Moreelucidate the interfacial reaction mechanism.(1)The hydrolysis rate of a hydrophilic substrate, acetylsalicylic acid, with alpha -chymotrypsin and lipase were measured in microemulsion. The reaction catalysed by hydrophobic lipase proceeds near the interface of microemulsion. On the other hand, the reaction by hydrophilic a -chymotrypsin proceeds in the water-pool of microemulsion, and the rate constant increased with the increase in water contents of microemulsion.(2)The hydrolysis rate of a hydrophobic substrate, 2-naphthy lacetate were also measured in microemulsion. Super-active behavior was observed in the reaction by lipase. On the other hand, the reaction for alpha -chymotrypsin was found to proceed in the water-pool of microemulsion and the rate constant increased with the increase in water contents.3. We carried out the preliminary experiments to elucidate the characteristic behavior of a membrane bioreactor for enzymatic reactions and also to examine the possibility of increasing the reaction yield of the hydrophobic substrate. flowever, the reaction yields could not be enhanced in these reaction systems. Therefore, experiments with the other hydrophobic substrates will be required in the further study. Less